Pertussis (whooping cough) is a highly contagious infection caused by the bacteria Bordetella pertussis, which results in fits of coughing that usually end in a prolonged, high-pitched, deeply indrawn breath (the whoop).
Pertussis usually affects children and adolescents.
Mild coldlike symptoms are followed by severe coughing fits, then gradual recovery.
The diagnosis is based on the characteristic whoop-sounding cough and examination of the mucus in the nose and throat.
Most children with pertussis recover slowly but completely.
Vaccination can help prevent this infection.
Very ill children usually are hospitalized and given antibiotics to eliminate the infection.
Pertussis, once rampant in the United States, is now better controlled although not eradicated. In 2013, there were 28,000 cases of pertussis in the United States. Local epidemics among unimmunized people occur every 2 to 4 years. Pertussis remains a major problem throughout the developing world.
Pertussis is the only childhood disease that is becoming more common even though it can be prevented by a vaccine. This increase may result from
People may develop pertussis at any age, but over 70% of cases occur in children younger than 5 years, and almost 40% of cases occur in infants younger than 6 months. Pertussis is most serious in children younger than 2 years, and nearly all deaths occur in children younger than 6 months. Most deaths are caused by pneumonia and complications affecting the brain. Pertussis is also serious in older people.
One attack of pertussis does not always give full immunity for life, but a second attack, if it occurs, is usually mild and not always recognized as pertussis. In fact, some adults with "walking pneumonia" actually have pertussis.
An infected person spreads pertussis bacteria into the air in droplets of moisture produced by coughing. Anyone nearby may inhale these droplets and become infected. Pertussis usually is not contagious after the third week of the infection.
The illness begins about 1 or 2 weeks after exposure. It lasts about 6 to 10 weeks, progressing through three stages:
Coldlike symptoms include sneezing, runny nose, loss of appetite, listlessness, a hacking cough at night, and a general feeling of illness (malaise). People may be hoarse but rarely have a fever.
Coughing fits develop after 10 or 14 days. These fits typically consist of 5 or more rapidly consecutive forceful coughs followed by the whoop (a prolonged, high-pitched, deeply indrawn breath). After a fit, breathing is normal, but another coughing fit follows shortly thereafter. The cough often produces large amounts of thick mucus (usually swallowed by infants and children or seen as large bubbles from the nose). In younger children, vomiting often follows a prolonged fit of coughing. In infants, choking spells and pauses in breathing (apnea), possibly causing the skin to turn blue, may be more common than the whoops.
About one fourth of children develop pneumonia, resulting in difficulty breathing. Ear infections (otitis media) also frequently develop. Rarely, pertussis affects the brain in infants. Bleeding, swelling, or inflammation of the brain may cause seizures, confusion, brain damage, and intellectual disability. Seizures are common among infants but rare in older children.
After several weeks, the coughing fits gradually subside, but for many weeks or even months, children have a lingering, persistent cough.
Most children with pertussis recover completely, although slowly. About 1 to 2% of the children under 1 year old die.
Doctors suspect pertussis because of the typical whooping cough or other symptoms. They confirm the diagnosis by culturing a sample of mucus from the back of the nose or throat. In people with pertussis, culture results are usually positive during the first two stages of illness but often are negative after several weeks of illness.
Other diagnostic tests (such as a polymerase chain reaction or rapid detection test) done on samples from the nose or throat may be helpful.
Children are routinely vaccinated against pertussis. The pertussis vaccine is usually combined with vaccines for diphtheria and tetanus as DTaP for children under 7 years and Tdap for adolescents and adults (see Figure: Vaccinating Infants and Children). Immunity from the vaccine tends to decrease 5 to 10 years after the last dose is given.
Experts recommend a single booster dose of Tdap for adolescents and for all adults after age 19 (including those over 65). A booster is also recommended during each pregnancy.
The antibiotic erythromycin (or sometimes clarithromycin or azithromycin) is given as a preventive measure to people of all ages who are exposed to pertussis whether they have been vaccinated or not.
If children under 7 years have received fewer than four doses of vaccine and they have close contact with someone who has pertussis, they should also be vaccinated.
Seriously ill infants are usually hospitalized because their breathing may become so difficult that they require mechanical ventilation through a tube placed in their windpipe. Some may need to have mucus suctioned from their throat. Others may need extra oxygen and fluids given by vein. Seriously ill infants are usually kept in isolation (to prevent other people from being exposed to infected droplets in the air—called respiratory isolation) until antibiotics have been given for 5 days. Because any disturbance can trigger a coughing fit, these infants are kept in a darkened, quiet room and disturbed as little as possible.
Older children who have mild disease are treated with antibiotics at home. Children treated at home should be isolated for at least 4 weeks after symptoms began and until symptoms resolve. Cough medicines are of questionable value and are not usually used.
The antibiotic erythromycin or azithromycin, taken by mouth, is usually used to eradicate the bacteria causing pertussis. Antibiotics are also used to treat infections that accompany the pertussis, such as pneumonia and ear infection.